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Mode I fracture toughness analysis of rubber particulate epoxy composite
Materials Today: Proceedings xxx (xxxx) xxx
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Mode I fracture toughness analysis of rubber particulate epoxy composite K.R. Chandan Reddy a, G. Bharathiraja a,⇑, V. Jayakumar a,b a b
Department of Mechanical Engineering, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai 601 105, Tamil Nadu, India Department of Mechanical Engineering, Amrita School of Engineering, Chennai, Amrita Vishwa Vidyapeetham, India
a r t i c l e
i n f o
Article history: Received 27 May 2019 Received in revised form 14 October 2019 Accepted 18 October 2019 Available online xxxx Keywords: Mode I fracture toughness Rubber particulate Waste tyre Hand layup Composite material
a b s t r a c t Tyres cannot be used in automobiles after completing their functional life. Every year one billion tyres are withdrawn from use in automobiles. In this study, rubber particulates obtained from waste tyres are used as reinforcement material in this composite. A new class of polymer composite is prepared using rubber particulate and epoxy resin as matrix material. Composite plates are manufactured by hand layup process. The five different volume fraction of rubber particulates are taken with epoxy resin material to fabricate composite plate. Then composite specimens are cut according to ASTM standard and Mode I fracture toughness test is carried out for the five test specimens. Test results show significant improvement in fracture toughness value for the increase in volume fraction of rubber particulate in epoxy material. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
1. Introduction Nowadays most of the research focusing on utilization of waste obtained from agricultural, industrial sector to prepare composite. This waste is simply dumped on soil which imposes threat to environment. Natural fillers and fibers like Rice husk, groundnut shell, walnut shell, almond shell, pineapple, coconut shell, sisal and coir, jute, palm, cotton, bamboo, wood etc. are widely used as reinforcement materials in polymer composites. It has been reported in literature [1,2]. Prakash Chandra Gope et al [3] investigated Mode I fracture toughness of bio fiber and bio filler reinforced epoxy composite. Banana fiber, bagasse fiber, coconut fiber and particles such as silica and walnut shell particle with different wt % were taken in hybrid form. Among banana bagasse and coconut fibers, bagasse based composite exhibited good fracture toughness value. Byung Chul Kim et al [4] predicted the fracture toughness of the nano particle reinforced epoxy composite. Nano particles like Nano clay, carbon black was taken and the fracture toughness was evaluated at room temperature and cryogenic temperature. Intermolecular force played a dominant role to predict the toughness values. The fracture toughness was measured using the single edge notched
⇑ Corresponding author.
bend specimen at the room (25 °C) and cryogenic temperature ( 150 °C). Based on the experimental results, it was found that nano-particles reinforcement in epoxy material improved the fracture toughness at the room temperature, but at cryogenic temperature, the fracture toughness decreased even though it has toughening effect. Sham Prasad et al. [5] investigated the Mode I inter laminar fracture toughness of silica particles- filled glass woven fabric reinforced Vinyl Ester composite. Inclusion of 6 wt% of silica particles in composite increases the tensile strength and show marginal improvement of tensile modulus. Singleton et al. [6] evaluated the fracture characteristics of the natural flax fiber and recycled high density polyethylene composite. The fracture characteristics of the composite are explained in terms of the principal deformation and failure mechanisms by optical microscopy and scanning electron microscopy. By varying fiber volume fraction, improvements in strength and stiffness combined with high toughness was achieved. Nowadays elimination of waste polymer is a global issue. Since these polymer materials are not easily decomposed, imposes a huge threat to environment. These tires consist of cross linked polymer structure and the presence of stabilizers and other additives make them high chemical stability [7]. Nowadays elimination of waste polymer is a global issue. Since these polymer materials are not easily decomposed, imposes a huge threat to environment. These tires consist of cross linked
E-mail address: [email protected] (G. Bharathiraja). https://doi.org/10.1016/j.matpr.2019.10.111 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
Please cite this article as: K. R. Chandan Reddy, G. Bharathiraja and V. Jayakumar, Mode I fracture toughness analysis of rubber particulate epoxy composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.10.111
2
K.R. Chandan Reddy et al. / Materials Today: Proceedings xxx (xxxx) xxx
polymer structure and the presence of stabilizers and other additives make them high chemical stability [8]. Most of the fracture work was focused on fracture study of composite under Mode I fracture condition [9,10]. Modified rubber is a well-known approach to improve the toughness of the fractures of fragile polymers. To achieve the optional strength effect, the failure mechanisms are clearly understood and the exact role the rubber plays in the tightening process is identified [11–13]. Crack growth and composite failure material in engineering applications rely on growth of micro cracks inherently present during manufacturing or produced under several stress cycles due to extensive use. Tear plays a significant role in failure mechanism of composite. Based on rubbing strength, composites exhibited improved toughness and properties [14,15]. In this work, five different volume fraction of rubber particulates were taken to study the fracture toughness of the composite under Mode I condition. Fig. 1. Test specimen.
2. Methodology 2.1. Materials In this work, rubber particulate from waste tyre, epoxy and hardener are taken as raw materials to fabricate composite specimens. Epoxy and hardener weight ratio is taken as 10:1. 2.2. Composite fabrication Previously, the tire rubber was micronized and dried at over 100 °C for 24 h. Five different volume fraction of rubber particulates (10, 15, 20, 25 and 30%) were taken. Hand lay-up process is used to prepare the composite with silicon rubber mold (300 300 3 mm). The micronized rubber is spread throughout the sheet, spraying on the epoxy resin. Resin and powder are often sprayed onto the mold surface together. At room temperature, curing can be done, immobilize it for 24 h. Table 1 shows the different volume fraction of reinforcement and epoxy taken. Fig. 2. Test specimen dimensions.
2.3. Fracture toughness testing The compact test specimens were cut according to ASTM D5045 standard (Fig. 1). Test specimen dimension is shown in Fig. 2. The crack will begin at the notch point and spread through the sample. In the field of mechanical fracture and corrosion testing, compact testing (CT) specimen are used extensively to determine material strength values. Experimental CT specimens are employed in cases where the compact design of the material is lacking. Fig. 3 depicts a typical fracture toughness testing machine used in this work. 2.4. Fracture mechanics and modes Fracture is a very important phenomenon to describe the material ability to resist the initiation crack and its propagation. Three different mode of fractures are there. The concept of mechanical
Table 1 Composite specimens fabricated. Specimen
1 2 3 4 5
% volume fraction Rubber particulate
Epoxy
10 15 20 25 30
90 85 80 75 70
Fig. 3. Fracture toughness testing machine.
fracture is same for Mode I, Mode 2 and Mode 3 fracture. In this study, the fracture toughness values of waste rubber polymer composite with five different volume fraction of particulate were calculated as per ASTM standard. Durability of fracture is determined by stress intensity factor. Critical stress intensity factor of composite plate with varying volume fraction of rubber particulates under Mode I condition is determined by analytical formula. It mainly depends on the thickness of test specimen, length as well as load applied on it.
Please cite this article as: K. R. Chandan Reddy, G. Bharathiraja and V. Jayakumar, Mode I fracture toughness analysis of rubber particulate epoxy composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.10.111
K.R. Chandan Reddy et al. / Materials Today: Proceedings xxx (xxxx) xxx Table 2 Fracture toughness test results of composite specimens. Specimen#
Volume fraction of rubber particulate
Epoxy resin
Fracture toughness KIC (pa.m1/2)
1 2 3 4 5
10% 15% 20% 25% 30%
90% 85% 80% 75% 70%
1.4 10 1.8 10 2.4 10 2.7 10 2.6 10
3 3 3 3
3
shown in Fig. 5. The increase of rubber particulate in epoxy matrix increases the fracture toughness values. At 25% volume fraction, the composite material exhibited good fracture toughness value. It is due to uniform dispersion of rubber particulate with epoxy resin material. After that agglomeration leads to the composite being amorphous in nature which decreases fracture toughness value.
3
4. Conclusion In this work, a new class of composite material using rubber particulate was prepared by hand layup method. Different volume fraction of rubber particulate was taken in epoxy resin. Then the Mode I fracture toughness test was carried out in testing machine. Crack durability of rubber powder epoxy composite gives a high strength at 25% volume fraction. Rubber particulate inclusion increases load carrying capacity of the composite to marginal level than neat epoxy. Ductility and stiffness of the composite is also improved which results in stable crack growth than catastrophic failure. This provides an encouraging result in utilizing waste rubber particulates in polymer composites. This kind of particulate reinforced polymer composite can be used in low load bearing structural applications like outer panels of lights and air conditioners.
Fig. 4. Load-displacement curve.
Declaration of Competing Interest
Fracture strength (pa.m1/2)
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References
Rubber % Fig. 5. Rubber particulate vs fracture strength.
3. Results and discussion Table 2 presents the fracture toughness testing results of the five composite specimens fabricated. Displacement behavior of the composite is shown in Fig. 4. It shows linear variation with respect to load. Due to rubber particulate dispersion makes stable crack growth instead of catastrophic failure of the composite. Based on test results obtained, the significant improvement in fracture toughness values for the increase of rubber particulate is
[1] J.J. Maya, T. Sabu, Carbohy. Polym. 71 (2008) 343–364. [2] O. Faruk, K. Andrzej, Bledzki, Hans-Peter Fink, M. Sain, Prog. Polym. Sci. 37 (2012) 1552–11496. [3] Prakash Chandra Gope, Vinay Kumar Singh, Dinesh Kumar Rao, J. Reinf. Plast. Comp. 34 (2015) 1075–1089. [4] Byung Chul Kim, Sang Wook Park, Dai Gil Lee, Compos. Struct. 86 (2008) 69– 77. [5] M.S. Sham Prasad, C.S. Venkatesha, T. Jayaraju, J Miner Mater Char Eng. 10 (2011) 1263–1275. [6] A.C.N. Singleton, C.A. Baillie, P.W.R. Beaumont, T. Peijs, Compos Part B Eng. 34 (2003) 519–526. [7] Roberta Sulcis, Luca Lotti, Serena Coiai, Francesco Ciardelli, Elisa Passaglia, J. Appl. Polym. Sci. 131 (2014) 40313. [8] M. Manoharan, J.J. Lewandowski, J. Compos. Mater. 25 (1991) 831–841. [9] S. Kunz-douglass, P.W.R. Beaumont, M.F. Ashby, J. Mater. Sci. 15 (1980) 1109– 1123. [10] Hung-Jue Sue, Polym. Eng. Sci. 31 (1991) 275–288. [11] Kavita Agarwal, D.K. Setua, G.N. Mathur, Defence Sci. J. 52 (2002) 337–346. [12] K.R. Harikrishnan, P.R. Deviprasad Varma, E. Shivakumar, Int. J. Eng. Trends Technol. 28 (2015) 307–310. [13] Xavier Colom, Javier Canavate, Fernando Carrillo, Eur. Polym. J. 42 (2006) 2369–2378. [14] Dong Yang Wu, Stuart Bateman, Matthew Partlett, Compos. Sci. Technol. 67 (2007) 1909–1919. [15] Ismat Zerin Luna, Krishna Chandra Dam, A.M. Sarwaruddin Chowdhury, Md. Abdul Gafur, Nuruzzaman Khan, Ruhul A. Khan, Adv,, Mater Sci Eng. 2015 (2015) 1–7.
Please cite this article as: K. R. Chandan Reddy, G. Bharathiraja and V. Jayakumar, Mode I fracture toughness analysis of rubber particulate epoxy composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.10.111
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Mode I fracture toughness analysis of rubber particulate epoxy composite K.R. Chandan Reddy a, G. Bharathiraja a,⇑, V. Jayakumar a,b a b
Department of Mechanical Engineering, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai 601 105, Tamil Nadu, India Department of Mechanical Engineering, Amrita School of Engineering, Chennai, Amrita Vishwa Vidyapeetham, India
a r t i c l e
i n f o
Article history: Received 27 May 2019 Received in revised form 14 October 2019 Accepted 18 October 2019 Available online xxxx Keywords: Mode I fracture toughness Rubber particulate Waste tyre Hand layup Composite material
a b s t r a c t Tyres cannot be used in automobiles after completing their functional life. Every year one billion tyres are withdrawn from use in automobiles. In this study, rubber particulates obtained from waste tyres are used as reinforcement material in this composite. A new class of polymer composite is prepared using rubber particulate and epoxy resin as matrix material. Composite plates are manufactured by hand layup process. The five different volume fraction of rubber particulates are taken with epoxy resin material to fabricate composite plate. Then composite specimens are cut according to ASTM standard and Mode I fracture toughness test is carried out for the five test specimens. Test results show significant improvement in fracture toughness value for the increase in volume fraction of rubber particulate in epoxy material. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
1. Introduction Nowadays most of the research focusing on utilization of waste obtained from agricultural, industrial sector to prepare composite. This waste is simply dumped on soil which imposes threat to environment. Natural fillers and fibers like Rice husk, groundnut shell, walnut shell, almond shell, pineapple, coconut shell, sisal and coir, jute, palm, cotton, bamboo, wood etc. are widely used as reinforcement materials in polymer composites. It has been reported in literature [1,2]. Prakash Chandra Gope et al [3] investigated Mode I fracture toughness of bio fiber and bio filler reinforced epoxy composite. Banana fiber, bagasse fiber, coconut fiber and particles such as silica and walnut shell particle with different wt % were taken in hybrid form. Among banana bagasse and coconut fibers, bagasse based composite exhibited good fracture toughness value. Byung Chul Kim et al [4] predicted the fracture toughness of the nano particle reinforced epoxy composite. Nano particles like Nano clay, carbon black was taken and the fracture toughness was evaluated at room temperature and cryogenic temperature. Intermolecular force played a dominant role to predict the toughness values. The fracture toughness was measured using the single edge notched
⇑ Corresponding author.
bend specimen at the room (25 °C) and cryogenic temperature ( 150 °C). Based on the experimental results, it was found that nano-particles reinforcement in epoxy material improved the fracture toughness at the room temperature, but at cryogenic temperature, the fracture toughness decreased even though it has toughening effect. Sham Prasad et al. [5] investigated the Mode I inter laminar fracture toughness of silica particles- filled glass woven fabric reinforced Vinyl Ester composite. Inclusion of 6 wt% of silica particles in composite increases the tensile strength and show marginal improvement of tensile modulus. Singleton et al. [6] evaluated the fracture characteristics of the natural flax fiber and recycled high density polyethylene composite. The fracture characteristics of the composite are explained in terms of the principal deformation and failure mechanisms by optical microscopy and scanning electron microscopy. By varying fiber volume fraction, improvements in strength and stiffness combined with high toughness was achieved. Nowadays elimination of waste polymer is a global issue. Since these polymer materials are not easily decomposed, imposes a huge threat to environment. These tires consist of cross linked polymer structure and the presence of stabilizers and other additives make them high chemical stability [7]. Nowadays elimination of waste polymer is a global issue. Since these polymer materials are not easily decomposed, imposes a huge threat to environment. These tires consist of cross linked
E-mail address: [email protected] (G. Bharathiraja). https://doi.org/10.1016/j.matpr.2019.10.111 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
Please cite this article as: K. R. Chandan Reddy, G. Bharathiraja and V. Jayakumar, Mode I fracture toughness analysis of rubber particulate epoxy composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.10.111
2
K.R. Chandan Reddy et al. / Materials Today: Proceedings xxx (xxxx) xxx
polymer structure and the presence of stabilizers and other additives make them high chemical stability [8]. Most of the fracture work was focused on fracture study of composite under Mode I fracture condition [9,10]. Modified rubber is a well-known approach to improve the toughness of the fractures of fragile polymers. To achieve the optional strength effect, the failure mechanisms are clearly understood and the exact role the rubber plays in the tightening process is identified [11–13]. Crack growth and composite failure material in engineering applications rely on growth of micro cracks inherently present during manufacturing or produced under several stress cycles due to extensive use. Tear plays a significant role in failure mechanism of composite. Based on rubbing strength, composites exhibited improved toughness and properties [14,15]. In this work, five different volume fraction of rubber particulates were taken to study the fracture toughness of the composite under Mode I condition. Fig. 1. Test specimen.
2. Methodology 2.1. Materials In this work, rubber particulate from waste tyre, epoxy and hardener are taken as raw materials to fabricate composite specimens. Epoxy and hardener weight ratio is taken as 10:1. 2.2. Composite fabrication Previously, the tire rubber was micronized and dried at over 100 °C for 24 h. Five different volume fraction of rubber particulates (10, 15, 20, 25 and 30%) were taken. Hand lay-up process is used to prepare the composite with silicon rubber mold (300 300 3 mm). The micronized rubber is spread throughout the sheet, spraying on the epoxy resin. Resin and powder are often sprayed onto the mold surface together. At room temperature, curing can be done, immobilize it for 24 h. Table 1 shows the different volume fraction of reinforcement and epoxy taken. Fig. 2. Test specimen dimensions.
2.3. Fracture toughness testing The compact test specimens were cut according to ASTM D5045 standard (Fig. 1). Test specimen dimension is shown in Fig. 2. The crack will begin at the notch point and spread through the sample. In the field of mechanical fracture and corrosion testing, compact testing (CT) specimen are used extensively to determine material strength values. Experimental CT specimens are employed in cases where the compact design of the material is lacking. Fig. 3 depicts a typical fracture toughness testing machine used in this work. 2.4. Fracture mechanics and modes Fracture is a very important phenomenon to describe the material ability to resist the initiation crack and its propagation. Three different mode of fractures are there. The concept of mechanical
Table 1 Composite specimens fabricated. Specimen
1 2 3 4 5
% volume fraction Rubber particulate
Epoxy
10 15 20 25 30
90 85 80 75 70
Fig. 3. Fracture toughness testing machine.
fracture is same for Mode I, Mode 2 and Mode 3 fracture. In this study, the fracture toughness values of waste rubber polymer composite with five different volume fraction of particulate were calculated as per ASTM standard. Durability of fracture is determined by stress intensity factor. Critical stress intensity factor of composite plate with varying volume fraction of rubber particulates under Mode I condition is determined by analytical formula. It mainly depends on the thickness of test specimen, length as well as load applied on it.
Please cite this article as: K. R. Chandan Reddy, G. Bharathiraja and V. Jayakumar, Mode I fracture toughness analysis of rubber particulate epoxy composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.10.111
K.R. Chandan Reddy et al. / Materials Today: Proceedings xxx (xxxx) xxx Table 2 Fracture toughness test results of composite specimens. Specimen#
Volume fraction of rubber particulate
Epoxy resin
Fracture toughness KIC (pa.m1/2)
1 2 3 4 5
10% 15% 20% 25% 30%
90% 85% 80% 75% 70%
1.4 10 1.8 10 2.4 10 2.7 10 2.6 10
3 3 3 3
3
shown in Fig. 5. The increase of rubber particulate in epoxy matrix increases the fracture toughness values. At 25% volume fraction, the composite material exhibited good fracture toughness value. It is due to uniform dispersion of rubber particulate with epoxy resin material. After that agglomeration leads to the composite being amorphous in nature which decreases fracture toughness value.
3
4. Conclusion In this work, a new class of composite material using rubber particulate was prepared by hand layup method. Different volume fraction of rubber particulate was taken in epoxy resin. Then the Mode I fracture toughness test was carried out in testing machine. Crack durability of rubber powder epoxy composite gives a high strength at 25% volume fraction. Rubber particulate inclusion increases load carrying capacity of the composite to marginal level than neat epoxy. Ductility and stiffness of the composite is also improved which results in stable crack growth than catastrophic failure. This provides an encouraging result in utilizing waste rubber particulates in polymer composites. This kind of particulate reinforced polymer composite can be used in low load bearing structural applications like outer panels of lights and air conditioners.
Fig. 4. Load-displacement curve.
Declaration of Competing Interest
Fracture strength (pa.m1/2)
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References
Rubber % Fig. 5. Rubber particulate vs fracture strength.
3. Results and discussion Table 2 presents the fracture toughness testing results of the five composite specimens fabricated. Displacement behavior of the composite is shown in Fig. 4. It shows linear variation with respect to load. Due to rubber particulate dispersion makes stable crack growth instead of catastrophic failure of the composite. Based on test results obtained, the significant improvement in fracture toughness values for the increase of rubber particulate is
[1] J.J. Maya, T. Sabu, Carbohy. Polym. 71 (2008) 343–364. [2] O. Faruk, K. Andrzej, Bledzki, Hans-Peter Fink, M. Sain, Prog. Polym. Sci. 37 (2012) 1552–11496. [3] Prakash Chandra Gope, Vinay Kumar Singh, Dinesh Kumar Rao, J. Reinf. Plast. Comp. 34 (2015) 1075–1089. [4] Byung Chul Kim, Sang Wook Park, Dai Gil Lee, Compos. Struct. 86 (2008) 69– 77. [5] M.S. Sham Prasad, C.S. Venkatesha, T. Jayaraju, J Miner Mater Char Eng. 10 (2011) 1263–1275. [6] A.C.N. Singleton, C.A. Baillie, P.W.R. Beaumont, T. Peijs, Compos Part B Eng. 34 (2003) 519–526. [7] Roberta Sulcis, Luca Lotti, Serena Coiai, Francesco Ciardelli, Elisa Passaglia, J. Appl. Polym. Sci. 131 (2014) 40313. [8] M. Manoharan, J.J. Lewandowski, J. Compos. Mater. 25 (1991) 831–841. [9] S. Kunz-douglass, P.W.R. Beaumont, M.F. Ashby, J. Mater. Sci. 15 (1980) 1109– 1123. [10] Hung-Jue Sue, Polym. Eng. Sci. 31 (1991) 275–288. [11] Kavita Agarwal, D.K. Setua, G.N. Mathur, Defence Sci. J. 52 (2002) 337–346. [12] K.R. Harikrishnan, P.R. Deviprasad Varma, E. Shivakumar, Int. J. Eng. Trends Technol. 28 (2015) 307–310. [13] Xavier Colom, Javier Canavate, Fernando Carrillo, Eur. Polym. J. 42 (2006) 2369–2378. [14] Dong Yang Wu, Stuart Bateman, Matthew Partlett, Compos. Sci. Technol. 67 (2007) 1909–1919. [15] Ismat Zerin Luna, Krishna Chandra Dam, A.M. Sarwaruddin Chowdhury, Md. Abdul Gafur, Nuruzzaman Khan, Ruhul A. Khan, Adv,, Mater Sci Eng. 2015 (2015) 1–7.
Please cite this article as: K. R. Chandan Reddy, G. Bharathiraja and V. Jayakumar, Mode I fracture toughness analysis of rubber particulate epoxy composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.10.111